Lecture 4

Question 1

Evidence for extinction? (3•)

Answer 1

•Fossil organisms that are not living today
•Darwin’s interpretation that species change
•The # of species have changed through time.

Question 2

Transitional forms?

Answer 2

Characteristics somewhat present between older and younger species.

Question 3

Evidence for transitional forms?

Answer 3

•Organisms are related
•Organisms occurred at different times.

Question 4

Pseudogenes?

Answer 4

Genes that are non-functional but have DNA sequences similar to that of functional genes.

Question 5

Genetic Homology?

Answer 5

Similarity in DNA or amino acid sequences in different species.

Question 6

Developmental Homologies?

Answer 6

Similarity in embryonic traits.

Question 7

Structural Homologies?

Answer 7

When specific structures are similar in different species (but maybe with different organization.

Question 8

What must happen for natural selection to occur?

Answer 8

•Traits must be heritable
•Genetic variation with a species for a trait
•The trait must increase fitness.

Question 9

Tuberculosis (TB)?

Answer 9

A potential fatal lung infection that is caused by the bacteria, Mycobacterium.

Question 10

Why can a mutation that can cause resistance to an antibiotic only occur if the antibiotic is present?

Answer 10

The mutation decreases fitness compared to others without the antibiotic but increases fitness compared to others with the antibiotic.

Question 11

Why can’t you assume that a phenotypic variation has a genetic basis?

Answer 11

Because phenotypes can depend on environmental cause.

Question 12

Adaptation?

Answer 12

Any heritable trait that increases the fitness of an individual.

Question 13

What criteria must be met for a trait to be an adaptation?

Answer 13

•Heritable
•Functional
•Adaptive
Trait must increase the fitness of the organism
•Current function
the trait evolved the same time as the current function.

Question 14

Natural selection only occurs when competition is present?

Answer 14

No

Question 15

!Acclimation?

Answer 15

When there is environmental changes and individuals are able to respond to them temporarily. (E.g. avoidance)

Question 16

Adaptation only occurs when?

Answer 16

A population changes in response to natural selection.

Question 17

Acclimation occurs in an individuals?

Answer 17

Lifespan

Question 18

Criteria for artificial selection?

Answer 18

•There must be genetic variation
•traits must have a genetic basis
•the trait is favoured by the gardener, not by differences in fitness

Question 19

Criteria for sexual selection?

Answer 19

•when traits are sexually preferable (many mating strategies by birds)

Question 20

Why is asymmetry in sex important for sexual selection?

Answer 20

When one sex has a trait that decreases fitness but increases fitness in another sex. The sex with the worse fitness can impress with the sex that has the better fitness.

Question 21

Evolution by natural selection changes the?

Answer 21

Population, not individual.

Question 22

What does it mean if a question concludes WITH CERTAINTY if an evolutionary mechanism is responsible?

Answer 22

It is always NO.

Question 23

!What are the three main reasons that genetic drift can alter allele frequencies randomly? (3•)

Answer 23

•Mating opportunities
•Survival
•Game contribution to the next generation.

Question 24

!When something is random, is it always truly random?

Answer 24

No (e.g. individuals may prefer to mate with an individual with a certain phenotype)